SYSTEM FOR DIFFERENTIAL PARTICLE COUNTING

• US 3,824,393 A
• Filed: 10/01/1973
• Issued: 07/16/1974
• Est. Priority Date: 08/25/1971
• Status: Expired due to Term

• Current Assignee: Alfred E. Brain
• Original Assignee: Alfred E. Brain
• Inventors: Brain, Alfred E.
• Primary Examiner(s): Lawrence, James W.
• Assistant Examiner(s): Nelms, D. C.
• Application Number:
  US05/402,656
• Time in Patent Office: 288 Days
• Field of Search: 356/39,40,41,42,102,103,207,208 250/222PC,226,339
• US Class Current: 250/222.1
• CPC Class Codes: G01N 15/1468 with spatial resolution of the texture or inner structure of the particle
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06M 11/04 with provision for distinguishing between different sizes of objects investigating particle size in general G01N15/00
• CPC Class Codes: G06T 2207/30024 Cell structures in vitro; Tissue sections in vitro
• CPC Class Codes: G06T 7/62 of area, perimeter, diameter or volume
• CPC Class Codes: G06T 7/66 of image moments or centre of gravity
• CPC Class Codes: G06V 10/20 Image preprocessing
• CPC Class Codes: G06V 10/40 Extraction of image or video features
• CPC Class Codes: G06V 20/69 Microscopic objects, e.g. biological cells or cellular parts

Abstract

A system for differentiating and counting particles and in particular nucleated particles such as white blood cells. The presence in the field of view of a particle of the type to be differentiated and counted is detected and an image of the field scanned by a television camera. An analog to digital converter samples the television camera output to provide a digital data representation of the intensity of a sampled field of picture elements of predetermined resolution. The digital data is processed by a digital computer including a memory for storing the sampled field of picture elements. Picture elements corresponding to a particle to be analyzed are circumscribed by box-finding algorithms and digital data corresponding to picture elements enclosed by the box are analyzed for parameters used in identifying the particle. Particles are identified by a distance measure or criterion of closeness to selected prototype particle points in an n dimensional space according to a preselected set of n parameters. Focus is automatically preserved during microscope imaging of a specimen passed beneath the microscope objective to insure reliable data for processing.

Claims

1. A system for differentiating and counting particles of the type in which an illuminated particle field is imaged by a microscope onto a scanning target comprising:

a beamsplitter positioned in the image beam path from the microscope, said beamsplitter positioned to direct a first portion of image light along a first path to the scanning target and to direct a second portion of image light along a second path;

a row of photocell means positioned in the second path from said beamsplitter; and

logic circuit means coupled with the output from said row of photocell means for generating a ready signal indicating the presence in the imaged field of a particle to be differentiated and counted.

2. A system for differentiating and counting particles as set forth in claim 1 wherein said scanning means comprises a television camera having a photocathode target on which the image of the flash illuminated specimen in the microscope objective field is temporarily stored for scanning and generating an electrical signal.

3. A system for differentiating and counting particles of the type in which a particle field is imaged by a microscope onto a scanning target comprising:

a first source of light for continuously illuminating the particle field with light in the infrared range;

a second light source for providing a flash illumination of the particle field upon the occurrence of a trigger signal;

a dichroic mirror beamsplitter means positioned in the image beam path from the microscope, said beamsplitter positioned to direct image light in the visible range to the scanning target and to pass image light in the infrared range in another direction;

a row of photocell means positioned in the infrared light path from said beamsplitter; and

logic circuit means coupled with the output from said row of photocells for generating a trigger signal indicating the presence in the image field of a particle to be differentiated and counted.

4. A system for differentiaTing and counting particles of the type in which a particle field is imaged by a microscope onto a scanning target comprising a first light source for illuminating the particle field with light of a first frequency range, a second light source for illuminating the particle field with light of a second frequency range, means for directing image light from the particles having the first frequency range to the scanning target and for directing image light from the particles of the second frequency range in another direction, sensing means positioned for receiving the image light of the second frequency range, means for generating a trigger signal in response to the receipt of light of the second frequency range by the sensing means, and means for momentarily activating the first light source with the trigger signal.